energy.analog.com

Project Code: APM-PLM-2014

A New Distribution Automation SolutionBased on the ADSP-CM40x Processor

Power Distribution SystemsIn the modern smart grid system, distribution automation systems will update to increasingly more intelligent electronic devices, which are used to monitor power quality and quickly isolate any fault from affecting the overall grid operation. Smart terminals, including DTU/FTU/TTU, are growing in use and changing grid architecture. Designing these devices requires processors, multichannel ADCs, signal condition circuits, a power supply, and communication interfaces. Robustness and cost became the main sources of pressure for equipment providers. Analog Devices, as the worldwide technical leader of mixed-signal processing, is the major electronic system solution supplier in power distribution systems and will give the solutions.

ADI Value PropositionADI offers best-in-class products to help designers building their systems.

• Expertise in integrated energy measurement—300 million ADI metrology-based meters deployed.

• Precision measurement of current and voltage through highly accurate converters and amplifiers.

• Enable robust and reliable power networks using high performance processing technology.

• 50% of all electrical grid equipment worldwide uses ADI converters.

• Mixed-signal conversion and processing enable ease of design, saving cost and reduced time to market.

• Compact design, smaller housing which leads to new system level architecture consideration.

System Design Considerations and Major Challenges• High channel account in the DTU-type application increases processor loads when using traditional system architecture.

• Same current sensing channel for protection and measurement functionality, which requires higher dynamic signal range.

• The integration of harmonic measurement functionality into terminal units requires a higher analog sampling rate and corresponding higher post signal processing calculation density.

• Due to more communication requirements in power distribution networks, IEC61850 compatibility will be necessary in the future.

• Robustness requirements such as overvoltage protection, EMC/EMI, operation temperature range over the standard industry requirement, a long lifetime, and more.

• Cost/functionality balance will be a key point for power distribution automation devices.

Why Use ADI Solutions?The ADSP-CM40x system in one package, with a rich set of industry-leading system peripherals and memory, is helpful for a compact layout and reducing design time.

• Decrease the overall system cost by using 16-bit, high precisions ADCs with low cost but high performance op amps.

• Offers an additional on-chip assistant hardware module—HAE (harmonic analysis engine)—to reduce the load of the MCU for post signal processing algorithms (for example, energy metrology and FFT). Provide an easy approach for the customer to realize a metering and protection automation device.

• Support two CAN buses for enhanced back plane communication, which increases communication bandwidth or provides system-level redundancy

• Enhanced back plane-based, system-level robustness by using a differential type communication interface.

• Integrated Ethernet MAC with IEEE1588 supported.

2 | A New Distribution Automation Solution Based on the ADSP-CM40x Processor

System Block Diagram• DTU System Architecture

ADC0

ADC1

AMP

BUF

BUF

AMP

ADSP-CM403CORTEX-M4

CORE

SIGNAL ACQUISITION BOARD

SIGNAL CONDITION

MILVDS

PT

PT

PT

CT

CT

CT

PT/CT

PT/CT

UP TO 24CHANNELS

±10V±5V

ADC0

ADC1

AMP

BUF

BUF

AMP

ADSP-CM403CORTEX-M4

CORE

SIGNAL ACQUISITION BOARD

SIGNAL CONDITION

MILVDS

PT

PT

PT

CT

CT

CT

PT/CT

PT/CT

UP TO 24CHANNELS

±10V±5V

ADC0

ADC1

AMP

BUF

BUF

AMP

ADSP-CM403CORTEX-M4

CORE

SIGNAL ACQUISITION BOARD

SIGNAL CONDITION

MILVDS

PT

PT

PT

CT

CT

CT

PT/CT

PT/CT

UP TO 24CHANNELS

±10V±5V

MAIN CONTROL BOARD

MILVDS

PROCESSOR

ISO

LAT

ED

CA

N B

US ADSP-CM403

CORTEX-M4 CORE

ADC0

ADC1

DAC0

DAC1

ANALOG SUBSYSTEM

ADCC

DACC

HARMONIC ANALYSISENGINGE (HAE)

SINC FILTERS

HARDWARE FUNCTIONS

• Signal Acquisition Subsystem

PROCESSOR

SYSTEM FABRIC

16kBL1 INSTRUCTION CACHE

UP TO 384kBPARITY-ENABLED

ZERO-WAIT-STATE SRAM

L1 CACHE & MEMORY

HARMONICANALYSIS ENGINE

(HAE)

SINC FILTERS

ISOLATEDΣ-∆

MODULATOR

HARDWARE FUNCTIONS

UP TO 2MBFLASH

L3 MEMORY

FAULTMANAGEMENT

EVENTCONTROL

PLL AND POWERMANAGEMENT

SYSTEMWATCHDOGS

SYSTEM CONTROL BLOCKS

ADC0

ADC1

DAC0

DAC1

ANALOG SUBSYSTEM

ADCC

DACC

AMP

BUF

BUF

AMP

SIGNALCONDITION

PT/CT

UP TO 24CHANNELS

PT/CT

±10V±5V

INT REF

EXT REF

PERIPHERALS

1 × TWI

4 × QUADRATURE

ENCODER

12 × PWMPAIRS

8 × TIMER

2 × CAN

3 × UART

2 × SPI

2 × SPORT

1 × EMAC

1 × SMC

USB FS OTG(OPTIONAL)

DISPLAY

ISOLATEDiCoupler®

(OPTIONAL)

EXTERNALSRAM

ISOLATEDRS-232

ISOLATEDRS-485

ISOLATEDCAN/USB

ETHERNET

INTERFACES

GP

IO

AC-TO-DCAC OR DC110V/220V

POWER MANAGEMENT

DC-TO-DC LDO POWERSUPERVISOR

energy.analog.com | 3

ADI Recommended

Processor ADSP-CM403F/CM408F

Signal ConditionAmplifier: AD8604Buffer: AD8601/AD8655

Reference ADR3425/ADR421

Isolated Σ-Δ Modulator AD7403

Power Management ADP2164/ADP2311/ADP2118

Interface

Isolated RS-232: ADM3252EIsolated RS-485: ADM2587EIsolated CAN: ADM3053M-LVDS Transceiver: ADN469xE

Power Supervisor ADM13305/ADM708

• HAE Function Block

IA, VA

IB, VB

IC, VC

HARMONIC ANALYSIS ENGINE (HAE)

PLL

CONFIGURATIONREGISTERS

HARMONIC ANALYZER

HARMONICCOMPONENTS

CALCULATIONS

HARMONIC ENGINE

RESULT MEMORY

F V RMS HNN V RMS

F V RMS HNN V RMS

F V RMS HNN V RMS

F V RMS HNN V RMS

F V RMS HNN V RMS

F V RMS HNN V RMS

F V RMS HNN V RMS

F V RMS HNN V RMS

HPF...

4 | A New Distribution Automation Solution Based on the ADSP-CM40x Processor

Notes: The signal chain above is representative of a typical DTU type application design. The technical requirements of the blocks vary, but the products listed in the table below are representative of solutions that meet some of those requirements

energy.analog.com | 5

Main Products Introduction

Part Number Description Key Features Benefits

Processor

ADSP-CM403F/ADSP-CM408F

Mixed-signal control processor with

ARM® Cortex™-M4

Up to 240 MHz ARM Cortex-M4 with floating-point unit, 384 kB SRAM, 2 MB flash, two 16-bit SAR ADCs with up to 24 multiplexed inputs, two 12-bit r-string DACs, harmonic analysis engine, sinc filters, CAN, UART, Ethernet MAC, PWM

System in package, ADC simultaneous sampling (up to 2.63 MSPS), 3-phase harmonic analysis, low static power consumption

Amplifier

AD8604Precision CMOS single supply op amp

Vos = 500 µV (max), single VSUPPLY = 2.7 V to 5.5 V, wide bandwidth: 8 MHz, slew rate: 5 V/µs

Low distortion, no phase reversal, RIO, low cost quad amplifier

Reference

ADR3425 Voltage referenceInitial accuracy: ±0.1% (max), temperature coefficient (max): 8 ppm/°C, operating temperature range: −40°C to +125°C

Low cost, SOT-23 package, 10 mA source and 3 mA sink reference

Isolated Σ-Δ Modulator

AD7403 Isolated Σ-Δ modulatorVSUPPLY: single 5 V, input range: differential ±250 mV, SNR: 88 dB typical, ENOB: 14.2 bits typical,1.6 µV/°C maximum offset drift, on-board digital isolator

Avoid Hall sensors to reduce cost;16-bit high resolution (±2 LSB INL typ)

Power Management

ADP2164Step-down (buck) switch regulator

Input voltage: 2.7 V to 6.5 V, 4 A output current, ±1.5% output accuracy, temperature range: −40°C to +125°C

Internal compensation and soft start, overvoltage/overcurrent protection, TSD

Interface

ADM2587E Isolated RS-485 transceiverisoPower® integrated isolated dc-to-dc converter, data rate: 500 kbps, 2.5 kV rms for 1 minute, ±15 kV ESD protection on RS-485 input/output pins, 5 V or 3.3 V operation

Eliminates the need for an external dc-to-dc isolation block, connect up to 256 nodes on one bus

ADM3053 Isolated CAN transceiver2.5 kV fully isolated (power and data), up to 1 Mbps data rate, slope control for reduced EMI

Connect 110 or more nodes on the bus, unpowered nodes do not disturb the bus

ADN4697E Multipoint LVDS transceiverSwitching rate: 200 Mbps (100 MHz), supported bus loads: 30 Ω to 55 Ω, high-Z when disabled or powered off

Glitch-free power-up/power-down, enhanced ESD protection on bus pins

Supervisor

ADM13305 Processor supervisorsDual supervisory circuits, VSUPPLY: single 2.7 V to 5.5 V, pretrimmed threshold options: 1.8 V, 2.5 V, 3.3 V, and 5 V, reset valid from VDD ≥ 1.1 V

On-chip watchdog timer, 8-lead, narrow body SOIC package

Designed by WPI Designed by Excelpoint

Design Resource

Reference Design/Demo DesignThe data acquisition board designed by our distributor: WPI and Excelpoint, which is based on the ADSP-CM40x processor and other ADI products to cover the full signal chain. Meanwhile, integrated voltage and current sensors on the board for more compact layout.

Technical Hotline

EmailEngineerZoneFree Samples

1-800-419-0108 (India)1-800-225-5234 (Singapore)0800-055-085 (Taiwan) 82-31-786-2500 (Korea)

cic.asia@analog.com

ez.analog.com

www.analog.com/sample

Customer Interaction Center

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ADI ContactIf you need more ADI energy applications and products information, please visit: energy.analog.com

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Application Notes/Technical Articles/Circuit Notes• Maximizing ADC Sampling Rate on ADSP-CM40x Mixed-Signal Control Processors (EE365)—www.analog.com/EE-365

• ADSP-CM40x Power Supply Transistor Selection Guidelines (EE361)—www.analog.com/EE-361

• Utilizing the Trigger Routing Unit for System Level Synchronization (EE360)—www.analog.com/EE-360

• ADSP-CM40x Serial Flash Execute-in-Place Technology (EE363)—www.analog.com/EE-363

• ADSP-CM403HAE-Harmonics-Analysis in Solar Applications (MS-2543)—www.analog.com/MS-2543

• LVDS and M-LVDS Circuit Implementation Guide (AN-1177)—www.analog.com/AN-1177

• Robust Completely Isolated Current Sense Circuit with Isolated Power Supply for Solar Photovoltaic Converters (CN0280)—www.analog.com/CN0280

Design Tool• www.analog.com/en/evaluation/cm40x-ez/eb.html